EXCHANGE 


Lib. 


JUL   31 


The  Fractionation  of  California 

Petroleum    by   Diffusion 

through  Fuller's 

Earth 


DISSERTATION 


SUBMITTED  TO  THE  BOARD    OF    UNIVERSITY  STUDIES  OI; 

THE  JOHNS  HOPKINS  UNIVERSITY  IN  CONFORMITY 

WITH  THE  REQUIREMENTS  FOR  THE  DEGREE 

OF  DOCTOR  OF  PHILOSOPHY 


BY 


PHILIP  SCHNEEBERGER 


JUNE,  1913 


EASTON,  PA. 

ESCHENBACH  PRINTING  Co. 
1913 


The  Fractionation  of  California 

Petroleum    by   Diffusion 

through  Fuller's 

Earth 


DISSERTATION 


SUBMITTED  TO  THE  BOARD   OF   UNIVERSITY  STUDIES  OF 

THE  JOHNS  HOPKINS  UNIVERSITY  IN  CONFORMITY 

WITH  THE  REQUIREMENTS  FOR  THE  DEGREE 

OF  DOCTOR  OF  PHILOSOPHY 


BY 

PHILIP  SCHNEEBERGER 

JUNE,  1913 


EASTON,  PA. 

ESCHENBACH  PRINTING  Co. 
1913 


TABLE  OF  CONTENTS. 

Page 

Acknowledgment 4 

Introduction 5 

Description  of  Petroleums 6 

Investigation  of  I  California  Oil 7 

Fractionation 10 

Determination  of  Sulphur 1 1 

Investigation  of  II  California  Oil 14 

Determination  of  Nitrogen 17 

Investigation  of  Benzene  and  Paraffin  Oil  19 

Investigation  of  III  California  Oil 30 

Preliminary  Fractionation 32 

Preliminary  Analyses 33 

Fractionation 35 

Sulphuric  Acid  Absorption 38 

Bromine  Absorption 39 

Proportion  of  Different  Hydrocarbons  Present 42 

Summary 45 

Biography 47 


ACKNOWLEDGMENT. 

The  author  wishes  to  express  grateful  acknowledgment  to 
Professors  Remsen,  Morse,  Jones,  Acree,  Gilpin  and  Lovelace 
for  instruction  in  the  lecture  room  and  laboratory.  He  also 
takes  this  opportunity  to  thank  Dr.  Gilpin,  under  whose  care- 
ful direction  this  investigation  was  carried  on,  for  valuable  sug- 
gestions and  practical  assistance  in  the  research;  Dr.  Frazer 
for  aiding  him  in  arriving  at  theoretical  deductions;  and  Dr. 
Day,  of  Washington,  for  helpful  suggestions  and  for  furnishing 
material  for  investigation. 


Fractionation    of  California  Petroleum 

by   Diffusion    through 

Fuller's  Earth.1 


For  several  years  investigations  have  been  in  progress  in 
this  laboratory  upon  the  effect  produced  by  diffusion  of  pe- 
troleum oils  through  fuller's  earth.  These  investigations  were 
pursued  in  order  to  obtain  some  idea  of  the  changes  produced 
in  the  process  of  diffusion  to  which  the  oils  have  been  sub- 
jected in  their  passage  from  the  place  of  formation  to  their 
present  location;  also,  to  gain  some  idea  of  the  substances 
present  in  the  natural  oil  by  a  separation  of  the  constituents 
by  a  process  not  involving  the  use  of  heat,  and  thereby  pro- 
ducing changes  by  cracking  and  otherwise.  The  results  ob- 
tained when  a  light  oil  from  Pennsylvania  and  a  heavier  oil 
from  Illinois  were  thus  fractionated  have  already  been  pub- 
lished.2 In  the  present  investigation,  this  method  of  fractiona- 
tion  was  extended  to  a  very  heavy  petroleum  from  California. 
As  will  be  later  described,  the  different  fractions  obtained  by 
such  diffusion  were  studied  with  regard  to  their  content  of 

1  This  research  was  aided  by  a  grant  received  from  the  C.  M.  Warren  Committee 
of  the  American  Academy  of  Arts  and  Sciences. 

2  Gilpin    and    Cram:      "The    Fractionation   of   Crude    Petroleum    by   Capillary 
Diffusion,"  Am.  Chem.  /.,  40,  No.  6,  December,    1908.     Gilpin  and  Bransky:    "The 
Diffusion    of    Crude   Petroleum   through   Fuller's  Earth,"    Ibid.,    44,    No.    3,    Sep- 
tember, 1910. 


paraffin,  benzene,  and  olefin  hydrocarbons,  and  to  the  amount 
of  sulphur  and  nitrogen  compounds  found  in  them  and  in  the- 
earth  through  which  they  passed.  For  the  sake  of  compari- 
son, the  behavior  of  mixtures  of  known  amounts  of  benzene 
and  pure  paraffin  oil,  when  allowed  to  diffuse  through  fuller's 
earth,  were  also  studied. 

DESCRIPTION   OF   OILS   USED 

California  Oil  L — Viscous,  brownish  black  in  color;  of  a 
syrupy  consistency,  and  failed  to  flow  from  a  small  vessel 
when  cooled  to  — 10°;  possessed  a  disagreeable  odor,  sugges- 
tive of  organic  sulphur  compounds;  specific  gravity  at  20°, 
0.912;  when  distilled,  the  first  fraction  came  over  at  90°, 
colorless  and  agreeable  in  odor;  the  last  fraction  came  at  380°, 
brown,  disagreeable  in  odor,  resembling  garlic,  but  supposed 
to  be  due  to  hydrides  of  the  hydrocarbons,  formed  during  the 
cracking  of  the  oil;  analysis  showed  appreciable  amounts  of 
sulphur  compounds  present.  This  oil  came  from  Kern  County, 
California. 

California  Oil  II. — Less  viscous  than  the  first  oil,  and  of 
less  disagreeable  odor;  specific  gravity,  taken  with  a  delicate 
Westphal  balance  at  20°,  0.8890;  when  distilled,  fractions 
were  obtained  from  100°  to  350°;  contained  a  small  proportion 
of  benzene  hydrocarbons  and  0.760  per  cent,  of  nitrogen 
compounds;  no  trace  of  sulphur  compounds  was  found.  The 
oil  came  from  Well  No.  i,  Section  30-30-24,  Elk  Hills,  Kern 
County. 

California  Oil  III. — Fairly  viscous,  brownish  black  oil, 
of  somewhat  disagreeable,  smoky  odor;  specific  gravity,  0.9118 
at  20°;  when  distilled,  fractions  were  obtained  from  105°  to 
340°,  attempts  to  obtain  fractions  at  higher  temperatures 
resulting  in  the  cracking  of  the  oil,  giving  fractions  ranging 
around  270°;  rich  in  benzene  and  olefin  hydrocarbons,  but 
entirely  free  from  nitrogen  and  sulphur  compounds;  its  prop- 
erties resembled  closely  those  of  the  first  California  oil.  The 
petroleum  came  from  Well  No.  i,  Section  30,  Elk  Hills,  Kern 
County. 

Pennsylvania  Oil. — A  light,  thin,  dark  brown  oil  from  Ve- 


nango  County,  Pennsylvania;  possessed  an  agreeable  odor; 
specific  gravity  at  20°,  0.8470.  This  was  the  same  oil  that 
had  been  investigated  by  Gilpin  and  Cram,  and  Gilpin  and 
Bransky.  Between  the  time  when  this  oil  was  first  studied 
and  its  investigation  in  1912  and  1913,  its  specific  gravity 
had  increased  from  0.810  to  0.8470  by  evaporation  through 
the  barrel  staves. 

INVESTIGATION   OF   CALIFORNIA   OIL   I 

The  oil  first  studied  was  the  heavy  petroleum  from  Kern 
County,  California.  A  description  of  this  oil,  named  the  Cali- 
fornia Oil  I,  is  found  on  page  6. 

The  method  of  handling  this  oil  was  practically  the  same  as 
that  introduced  by  Gilpin  and  Cram  and  improved  by  Gilpin 
and  Bransky.  The  apparatus  in  which  the  diffusion  was  car- 
ried out  was  similar  to  that  employed  by  Gilpin  and  Bransky. 
Two  minor  additions  were  made  to  the  apparatus.  The  first 
of  these  was  a  manometer  which  recorded  pressures  from  730 
mm.  to  o  mm.  when  attached  to  the  exhaust  system.  The 
other  was  a  device  which  it  was  found  necessary  to  put  in  series 
with  the  exhaust  system,  owing  to  the  fact  that  the  exhaust 
was  obtained  by  use  of  a  large  Chapman  water  pump.  Fluc- 
tuations in  the  water  pressure  were  accompanied  by  fluctua- 
tions in  the  amount  of  exhaust.  The  device  by  which  the  suc- 
tion could  be  maintained  uniform  for  any  length  of  time 
consisted  of  a  sliding  tube  with  perforations  at  its  lower  end, 
that  could  be  adjusted  by  raising  or  lowering  in  a  reservoir 
of  mercury  according  as  lower  or  higher  pressures  were  de- 
sired. 

It  was  found  at  the  start  that  an  oil  as  heavy  as  this  one 
could  not  be  made  to  diffuse  of  itself  by  capillarity  at  room  tem- 
peratures (19°  to  23°).  To  produce  the  necessary  diffusion, 
reduced  pressures  were  brought  to  bear,  pressures  as  low  as 
12  mm.  of  mercury  being  maintained  for  days  at  a  time. 

In  the  preliminary  experiments,  sixteen  tubes  were  filled 
with  fuller's  earth.1  The  tubes  were  filled  by  dropping  into 
them  an  amount  of  earth  that  would  form  a  column  about  a 

1  This  earth,  known  as  "XXF  Clay,"  and  the  fuller's  earth   used   in  later  work 
were  obtained  by  courtesy  of  the  Atlantic  Refining  Co.,  Philadelphia,  Pa. 


8 

foot  in  height.  Since  all  ranges  of  compactness  of  the  earth 
were  desired,  the  earth  in  some  tubes  was  not  compressed  in 
any  way.  In  others  it  was  rammed  slightly  by  a  rod  tipped 
with  a  rubber  stopper,  In  a  third  set,  it  was  rammed  fairly 
hard,  and  in  a  fourth  as  hard  as  possible.  The  tubes  were 
then  allowed  to  stand  undisturbed  for  a  short  while,  so  as  to 
permit  the  cushions  of  air  held  between  layers  of  the  earth  to 
escape.  A  second  column  of  earth  a  foot  in  height  was  then 
added,  the  same  degree  of  packing  observed,  and  the  process 
repeated  until  the  tubes  were  filled.  They  were  then  placed 
with  their  lower  ends  in  separate  reservoirs  of  oil,  and  a  re- 
duced pressure  of  600  mm.  was  then  applied  to  the  upper 
ends.  This  failed  to  produce  any  diffusion,  as  could  be  deter- 
mined by  the  level  of  the  oil  in  the  reservoirs,  so  the  pressure 
was  gradually  reduced  until  20  millimeters  of  mercury  were 
registered  on  the  manometer.  There  was,  however,  no  sign 
of  actual  fractionation  of  the  oil  in  any  of  the  tubes,  but,  in- 
stead, at  the  low  pressure  that  was  employed  the  oil  was  drawn 
up  through  the  earth  unchanged  in  any  of  its  properties. 

An  explanation  of  the  failure  of  the  oil  to  fractionate  was 
found  in  the  high  viscosity  of  the  petroleum.  The  oil,  instead 
of  diffusing  through  each  minute  particle  of  earth,  was  sucked 
around  the  particles  and  emerged  unaltered  at  the  top  of  the 
tube. 

The  cause  of  the  high  viscosity  of  the  oil  was  doubtless  the 
very  large  quantity  of  bitumen  and  the  complex  hydrocar- 
bons present,  whose  boiling  points  were  as  high  as  380°.  Ac- 
cordingly, efforts  were  directed  toward  reducing  the  viscosity 
of  the  oil  by  coagulating  the  bitumen.  It  was  shaken  with  a 
solid  electrolyte  and  with  a  solution  of  the  same,  but  repeated 
experiments  failed  to  show  any  perceptible  reduction  in 
specific  gravity  or  viscosity,  nor  was  there  any  noticeable 
coagulation  of  the  bituminous  material  held  in  suspension 
in  the  oil. 

It  was  observed,  however,  that  any  rise  in  temperature 
of  the  oil  was  accompanied  by  a  marked  decrease  in  viscosity. 
Accordingly,  the  effect  of  this  reduction  in  viscosity  upon  the 
fractionation  of  the  crude  petroleum  was  next  studied.  In 


order  to  secure  uniform  conditions,  it  was  deemed  advisable 
to  have  the  reservoirs  for  the  oil  and  also  the  lower  part  of 
the  tubes  immersed  in  a  large  water  bath,  the  temperature  of 
which  could  be  regulated  and  maintained  uniform  by  a  gas 
thermostat.  An  appliance  that  could  withstand  the  action 
of  the  heated  water  and  oil  was,  therefore,  devised.  Glass  bot- 
tles, fitted  with  water-tight  stoppers  and  safety  tubes,  could 
not  be  employed,  for  these  broke  when  temperatures  above 
60°  were  reached.  For  the  fractionation  at  high  tempera- 
tures, each  tube  was  constructed  of  brass,  and  was  made  to 
fit  snugly  into  a  closed  reservoir  of  a  liter  in  volume.  Contact 
between  the  tube  and  the  neck  of  the  reservoir  was  made  per- 
fect by  having  a  lead  washer  which  was  held  rigidly  between 
the  two  by  a  nut  that  screwed  down  upon  the  neck  of  the 
reservoir. 

To  determine  the  most  desirable  temperature  at  which  the 
experiments  should  be  carried  out,  the  viscosity  of  the  oil 
was  measured  at  different  temperatures.  The  apparatus 
was  the  same  as  used  by  a  previous  experimenter.1  With 
the  viscosimeter  it  was  found  that  a  measured  quantity  of 
the  oil  used  by  Bransky  diffused  at  the  following  rates: 

4.5  cc.  of  Pennsylvania  Oil  (sp.  gr.  0.8470) : 

Minutes 

At  20°  10.25 

At  40°  6.00 

When  a  similar  quantity  of  the  California  Oil  I  was  run 
through  the  viscosimeter,  it  was  found  that  the  time  required 
was  vastly  greater.  The  following  results  were  obtained  at 
different  temperatures : 

Table  I 
4.5  cc.  California  Oil  I  (sp.  gr.  0.912) 

Minutes 

At  20°  84.0 

At  40°  41.0 

At  60°  17.5 

At  75°  ii. 3 

At  90°  8.1 

1  Am.  Chem.  /.,  44,  No.  3. 


10 

From  the  above  results,  it  is  apparent  that  a  temperature 
of  at  least  75°  is  necessary  for  diffusion,  since  the  viscosity  of 
the  oil  at  lower  temperatures  was  so  great  as  to  prevent  its 
fractionation  by  diffusion.  The  temperature  of  90°  was  ruled 
out  because  at  that  temperature  there  was  a  tendency  for  the 
lightest  ingredients  of  the  oil  to  distil  off.  This  was  deter- 
mined by  keeping  a  measured  quantity  of  the  oil  at  90°  for  a 
week.  A  quantity  amounting  to  about  two  per  cent,  was 
found  to  distil  off.  For  this  reason  it  was  deemed  advisable 
to  carry  on  the  diffusion  of  the  oil  at  75°. 

Accordingly,  eight  tubes  packed  with  varying  degrees  of 
hardness  were  maintained  at  75°,  and  at  the  end  of  nine  days 
these  yielded  the  first  fractions  of  the  heavy  California  oil 
(specific  gravity,  0.912).  Nearly  90  liters  of  the  oil  had  to 
be  used  to  obtain  the  four  fractions  in  the  amounts  shown  be- 
low: 

Table  II — First  Fractionation  of  California  Oil  I 

Quantity 
Fraction  Sp.  gr.  Liters 

I-A  0.86951  1.2 

i-B  0.882  1.4 

i-C  0.9025  1.8 

i-D  0.904  1.75 

Total     6.15 

There  was  thus  secured  a  small  proportion  of  available  frac- 
tions. This  was  obtained,  however,  only  after  very  great 
difficulties  had  been  overcome  and  with  a  loss  of  nearly  93 
per  cent,  of  the  original  oil.  The  results  demonstrate,  never- 
theless, the  possibility  of  fractionating  a  heavy,  viscous  petro 
leum.  Owing  to  the  difficulties  encountered  in  working  with 
large  quantities  of  the  oil  at  elevated  temperatures,  it  was  de- 
cided to  discontinue  work  on  this  heavy  petroleum  until  more 
adequate  means  of  handling  it  under  the  necessary  conditions 
were  at  the  disposal  of  the  experimenter. 

The  four  fractions  from  the  California  Oil  I,  designated  as 
i-A,  i— B,  i-C  and  i-D,  were  then  analyzed  for  their  sulphur 

1  All  specific-gravity    measurements  were  taken  at  exactly  20"  with  a  delicate 
Westpbal  balance. 


II 

content.     Similar  determinations  were  made  for  the  oil  re- 
tained by  the  earth. 

Determination  of  Sulphur  Compounds  in  the  California  Oil  I 

The  odor  of  the  high-boiling  fractions  of  this  oil  led  to  the 
suspicion  that  sulphur  compounds  were  present.  Accordingly, 
qualitative  tests  were  made  to  detect  the  presence  of  this 
element.  These  tests  were  as  follows : 

About  10  cc.  of  the  sample  to  be  tested  were  heated  to  boil- 
ing in  a  flask  provided  with  a  reflux  condenser.  About  half 
a  gram  of  metallic  sodium  was  introduced,  and  the  liquid  heated 
to  the  boiling  point  for  about  thirty  minutes.  After  cooling 
to  room  temperature,  water  was  gradually  introduced  through 
the  condenser  and  the  flask  shaken  until  the  sodium  had  gone 
into  solution.  The  solution  of  the  hydroxide  containing  the 
sodium  sulphide  was  separated,  and  the  addition  of  sodium 
nitroprusside  produced  a  purplish  blue  or  deep  purple  colora- 
tion. A  quicker  method  for  the  qualitative  determination  of 
sulphur  was  one  that  is  employed  in  the  petroleum  industry. 
A  solution  of  litharge  in  concentrated  potassium  hydroxide 
solution  was  prepared.  The  undissolved  litharge  was  allowed 
to  settle,  and  the  clear  solution  decanted.  Several  cc.  of  the 
oil  to  be  tested  were  shaken  with  a  small  quantity  of  the  potas- 
sium plumbite  solution,  and  the  oil  allowed  to  rise.  The  plumb- 
ite  solution  was  colored  from  pale  brown  to  black,  according  to 
the  amount  of  sulphur  present. 

Quantitative  determination  of  sulphur  by  the  usual  Carius 
method  failed,  the  bombs  exploding  in  every  one  of  the  fifteen 
analyses  that  were  attempted.  Carius  determinations  made 
in  hard  glass  tubes  gave  no  better  results.  A  modified  Carius 
method  was  then  employed.  This  was  essentially  as  follows: 
A  weighed  sample  of  the  oil  was  introduced  into  a  Carius  tube 
and  5  cc.  of  fuming  nitric  acid  were  poured  upon  it.  The  open 
tube  was  then  heated  for  two  hours  in  a  water  bath  at  100°. 
Five  more  cc.  of  the  acid  were  then  added,  and  the  heating  re 
peated  for  two  more  hours.  Then  five  cc.  of  the  acid  were 
again  introduced,  the  tube  was  drawn  out  and  sealed,  and  then 
heated  for  two  hours  in  a  bomb  furnace  at  280°.  The  charge 


12 

| 

of  the  tube,  when  cool,  was  emptied  into  several  hundred  cc. 
of  water,  and  the  sulphur  determined  as  barium  sulphate  by 
the  usual  method.  This  modified  Carius  method  gave  results 
that  were  somewhat  lower  than  the  results  obtained  by  the 
methods  finally  employed.  This  was  probably  due  to  the 
volatilization  of  the  sulphur  compounds  when  the  open  tube 
was  heated. 

The  methods  found  to  be  most  satisfactory,  however,  were  the 
Sauer  combustion  method,  described  in  detail  in  Morse's  Exer- 
cises in  Quantitative  Chemistry  (pp.  258-60),  and  a  method 
by  which  the  oil  was  oxidized  in  a  flask  by  concentrated  nitric 
acid  and  potassium  chlorate.  The  two  methods  gave  con- 
cordant results.  In  every  instance  duplicate  analyses  were 
made,  and  the  mean  result  given  in  the  table  below.  The  frac- 
tions analyzed  were  those  described  on  p.  jo- 

Table  111 — Analysis  for  Sulphur 

Fraction  Sp.  gr.  Per  cent,  sulphur 

i-A  o . 8695  o .  1 1 

i-B  0.882  0.144 

i-C  0.9025  0.174 

i-D  0.904  0.29 

Crude  oil  0.912  o*54i 

In  order  to  see  if  the  proportion  of  sulphur  could  be  further 
reduced  by  filtration  through  fuller's  earth,  Fractions  A  and 
B  were  refractionated  and  the  results  of  the  second  fractiona- 
tion  were  analyzed  with  respect  to  their  sulphur  content.  The 
fractions  from  A  are  designated  as  i-A  i,  i-A  2  and  i-A3; 
those  from  i-B  as  i-B  i,  i-B  2  and  i-B  3. 

Table  IV — Second  Fractionation:  Analysis  for  Sulphur 

Fraction  Sp.  gr.  Per  cent,  sulphur 

-A  i  0.^57  0.06 

-A  2  0.8604  0.07 

»       -A  3  0.869  °-  IO4 

-B  i  0.8625  0.072 

-B  2  0.8771  0.09 

-B  3  0.8803  0.141 


The  results  tabulated  above  show  that  there  is  a  gradual 
absorption  of  sulphur  compounds  by  the  fuller's  earth.  Those 
fractions  that  collect  at  the  top  of  the  tubes  have  the  smallest 
proportion  of  the  sulphur  compounds  in  them,  and  the  amount 
increases  as  fractions  lower  down  are  taken.  The  explanation 
of  the  comparatively  small  amount  of  sulphur  in  the  upper- 
most fraction  is  probably  as  follows:  the  original  petroleum 
penetrates  a  grain  of  the  porous  fuller's  earth,  emerges  on  the 
other  side  and  has  a  portion  of  its  sulphur  removed  and  re- 
tained by  the  earth.  The  possible  mechanism  of  this  selective 
absorption  by  the  earth  is  discussed  later.  The  oil  then  enters 
another  grain  of  earth,  the  absorptive  action  of  the  earth 
is  repeated,  and  more  of  the  sulphur  is  removed.  The  oil 
that  thus  penetrates  by  diffusion  up  to  the  top  of  the  tube  has 
passed  through  the  greatest  number  of  grains  of  earth  and  thus 
contains  less  sulphur  than  the  oil  that  has  not  penetrated 
so  far.  Moreover,  the  oil  that  follows  in  the  track  of  the  first 
particle  of  oil  which  penetrates  the  earth  finds  particles  of  earth 
that  have  already  taken  up  the  greatest  quantity  of  sulphur 
that  is  possible  for  them  to  absorb.  Hence  the  second  particle 
of  oil  passes  through  earth  that  is  already  saturated  with  re- 
spect to  its  power  to  absorb  sulphur  compounds,  and  it  may 
pass  through  unchanged,  or  nearly  so.  This  accounts  for  the 
fact  that  the  fractions  that  are  nearest  to  the  original  petro- 
leum have  chemical  and  physical  properties  that  closely  re- 
semble those  of  the  crude  petroleum. 

Judging  from  the  results  obtained  from  the  second  frac- 
tionation,  it  is  probable  that  if  enough  of  the  lighter  fractions 
were  available  for  carrying  on  several  more  fractionations, 
the  sulphur  could  be  entirely  removed. 

In  order  to  show  to  what  extent  the  earth  retained  the  sul- 
phur compounds  which  were  originally  in  the  oil,  the  earth 
from  which  the  oil  had  been  displaced  by  the  addition  of 
water  was  extracted  with  ether.  By  this  process,  oils  were  ob- 
tained which  were  heavier  than  those  oils  expelled  by  the  ad- 
dition of  water.  These  were  analyzed  for  sulphur,  with  the 
following  results: 


14 
Table  V — Analysis  of  Oil  Retained  by  Earth 

Section  of  earth  Sp.  gr.  Per  cent,  sulphur 

Oil  extracted  from  A  o .  8955  o .  1 1 

Oil  extracted  from  B  0.9038  0.237 

Oil  extracted  from  C  0.9105  0.42 

Oil  extracted  from  D  0.927  0.675 

These  results  show  that  it  is  undoubtedly  the  earth  through 
which  the  oils  pass  that  retains  the  sulphur  compounds.  They 
show,  moreover,  that  the  earth  in  the  lowest  parts  of  the  tube 
absorbs  so  much  of  the  sulphur  compounds  from  the  oil  that 
passes  through  them  that  the  proportion  of  these  compounds 
in  the  lower  end  of  the  tube  indicates  a  concentration  that  is 
greater  than  that  in  the  original  petroleum. 

INVESTIGATION   OF   CALIFORNIA   OIL   II 

In  working  with  the  heavy  California  petroleum  from  which 
the  fractions  described  above  were  obtained  by  diffusion  at 
elevated  temperatures,  it  was  pointed  out  that  such  fractiona- 
tion  was  exceedingly  difficult  to  effect,  and  at  an  enormous 
loss  of  petroleum.  Owing  to  these  results  a  lighter  oil  from 
the  same  locality  was  secured.  This  lighter  oil  was  the  one 
described  as  the  California  Oil  II  (see  p.  8).  Its  properties 
were  somewhat  different  from  the  oil  first  studied.  The  prin- 
cipal physical  differences  noted  were  viscosity  and  specific 
gravity,  the  latter  being  o.  889  in  contrast  to  0.912,  that  of  the 
California  Oil  I.  The  viscosity  was  taken  at  various  tempera- 
tures with  the  following  results: 

Table   VI — Viscosity  Measurements  of    California  Oil  II  (4.5 
cc.  Run  Through) 

Time 
Temperature  of  oil  Minutes 

2O°  24.0 

30°  I7.I 

40°  12.2 

50°  9-1 

It  was  decided  to  work  with  this  oil  at  room  temperature, 
owing  to  the  difficulties  arising  from  the  fractionation  of  large 
quantities  of  oil  at  elevated  temperatures.  Attention  was 


15 

then  turned  toward  the  problem  of  finding  the  length  of  tube 
most  desirable  for  fractionating  an  oil  of  specific  gravity 
0.889  at  20°. 

It  was  necessary,  in  addition,  to  ascertain  the  proper  amount 
of  pressure  that  should  be  brought  to  bear  to  bring  about  diffu- 
sion. For  this  purpose  glass  tubes  of  3 . 2  cm.  in  diameter  and 
varying  in  length  from  30  to  150  cm.  were  employed.  The 
object  in  using  glass  tubes  was  to  enable  the  observer  to  see 
to  what  extent  fractionation  was  taking  place  as  the  amount 
of  pressure  on  the  tubes  was  changed.  It  was  soon  found 
that  a  fractionation  of  the  petroleum  could  be  produced  work- 
ing at  room  temperatures.  While  the  results  obtained  were 
not  as  satisfactory  as  those  obtained  with  light  Pennsylvania 
oil  of  specific  gravity  0.8470,  they  demonstrated  the  possi- 
bility of  fractionating  an  oil  of  specific  gravity  0.889  by  dif- 
fusion through  fuller's  earth  at  ordinary  temperatures.  The 
yield  of  available  fractions,  however,  amounted  to  only  twenty 
per  cent,  of  the  oil  used,  while  in  the  case  of  the  lighter  Penn- 
sylvania oil,  it  was  45  to  50  per  cent,  of  the  petroleum  used. 

The  length  of  tube  that  gave  the  most  satisfactory  results 
was  found  to  be  about  90  cm.  The  degree  of  compactness  of 
the  earth  that  gave  best  results  was  obtained  by  tapping  the 
sides  of  the  tube,  and  refraining  from  ramming,  as  all  previous 
packing  had  been  done.  A  column  of  earth  a  foot  long  was  in- 
troduced into  the  tube,  and  it  was  tapped  lightly  on  its  side 
until  the  top  of  the  column  presented  a  firm  surface. 

The  method  employed  in  extracting  the  oil  from  the  earth 
into  which  it  diffused  consisted  in  taking  measured  sections 
from  the  earth1  after  it  had  been  carefully  emptied  into  a  cyl- 
inder that  was  split  longitudinally,  and  adding  water  to  each 
section.  The  water  formed  a  thick  emulsion  with  the  earth 
and  expelled  a  part  of  the  oil,  retaining,  however,  an  oil  that 
was  heavier  than  that  expelled.  It  was  noticed  that  the 
lighter  oils  were  displaced  in  much  greater  proportion  than 
were  the  heavier  oils,  for  the  earth  showed  a  tendency  to  re- 
main in  mechanical  combination  with  the  oil,  holding  almost 

1  The  section  of  earth  from  the  uppermost  part  of  the  tube  was  called  A,  and  the 
oil  extracted  therefrom  called  2-A.  The  next  lower  section  was  called  B,  and  its  oil 
2-B,  etc. 


i6 

100  per  cent,  if  the  specific  gravity  approached  0.9.  When 
an  examination  of  the  oil  retained  by  the  earth  was  desired, 
the  oil  was  extracted  from  the  dried  earth  by  ether.  By  the 
ether  extraction  an  oil  of  different  physical  and  chemical 
properties  was  secured.  This  proved  that  the  fractions  ob- 
tained by  displacement  of  the  oil  by  water  did  not  represent 
the  actual  fractions  formed  during  diffusion  through  the  earth, 
but  only  a  small  part  of  such  fractions. 

The  method  of  securing  fractions  of  oil  by  displacement  by 
water  was  then  dispensed  with  and  another  method  intro- 
duced. This  consisted  in  allowing  the  oil  to  diffuse  to  the  top 
of  the  tube  and  then  letting  it  overflow  into  small  tubes  of 
about  70  cc.  capacity.  The  oil  that  first  overflowed  and  col- 
lected in  the  upper  reservoir  constituted  the  first  fraction. 
The  first  fraction  was  usually  very  light  in  color  and  specific 
gravity.  As  the  diminished  pressure  continued  to  be  applied, 
a  heavier  oil  began  to  flow  into  the  upper  reservoir.  When 
a  change  in  color  was  noticeable,  the  reservoir  was  emptied 
or  exchanged  for  another,  and  the  pressure  was  temporarily 
cut  off  from  the  tube  by  means  of  pinchcocks  while  the  change 
was  being  made.  The  second  fraction  was  then  collected 
until  a  change  in  color  was  noticed,  and  so  on  with  a  third, 
until  an  oil  that  was  colored  brown  by  the  bitumen  of  the 
petroleum  drained  into  the  upper  reservoir.  The  reduced 
pressure  was  then  cut  off,  the  tubes  cleaned  and  refilled  with 
fresh  fuller's  earth,  and  the  process  repeated. 

By  repeated  experiment,  the  amount  of  pressure  that  gave 
the  best  results  was  determined  and  regulated  as  follows: 
the  tubes  were  allowed  to  stand  in  the  reservoirs  of  petroleum 
for  abour  24  hours,  without  any  reduced  pressure  being  ap- 
plied. Then,  for  a  period  of  about  three  days,  the  pressure 
was  gradually  reduced  until  the  manometer  registered  650 
mm.  of  mercury.  After  being  maintained  at  this  height  for 
several  days,  the  pressure  was  then  lowered  to  500  mm.  and 
kept  there  until  the  first  fractions  overflowed  into  the  upper 
reservoirs.  When  this  pressure  failed  to  draw  up  a  slow, 
steady  stream  of  oil  into  the  reservoirs,  it  was  still  further  re- 


17 

duced,  usually  being  made  as  low  as  200  mm.,  by  the  time 
that  the  last  available  fraction  had  been  collected. 

By  this  method  of  operating,  the  California  Oil  II  was  found 
to  be  capable  of  fractionation  into  five  distinct  fractions. 
The  lightest,  termed  Fraction  2-A,  was  of  specific  gravity 
0.8264;  the  heaviest,  2-E,  0.8737,  showing  a  wide  range  in 
density  (see  p.  18)- 

The  basis  upon  which  the  various  fractions  were  differ- 
entiated was  their  color,  as  it  was  observed  that  the  depth 
of  color  was  an  approximate  measure  of  the  specific  gravity 
of  the  oil. 

The  fractions  2-A  to  2-E  were  examined  for  nitrogen, 
and  all  of  them  showed  signs  of  its  presence.  Careful  anal- 
yses of  these  were  then  made,  and  similar  analyses  of  the  earth 
in  various  parts  of  the  tube  were  made.  Fractions  2-A  and 
2-B  were  then  subjected  to  a  second  fractionation,  and  the 
results  also  studied  with  regard  to  their  nitrogen  content. 

Determination  of  Nitrogen  Compounds  in  California  Oil  II 

Nitrogen  compounds  were  found  to  exist  in  the  California 
Petroleum  II  to  the  extent  of  nearly  0.8  per  cent.  Accord- 
ingly, this  oil  was  subjected  to  fractionation  by  the  improved 
method  that  was  adopted  by  the  investigator  (see  p.  16). 
This  was  necessary  since  the  oil  was  too  heavy  to  be  worked 
by  the  method  of  Cram  and  Bransky  unless  elevated  tempera- 
tures were  resorted  to  in  order  to  reduce  the  viscosity.  Be- 
sides, it  was  feared  that  high  temperatures  would  bring  about 
the  loss  of  the  nitrogen  compounds  by  volatilization. 

The  method  for  determining  the  nitrogen  was  that  known 
as  the  Gunning-Arnold-Dyer  modification  of  the  Kjeldahl 
method.  It  is  described  in  detail  in  Sherman's  Organic  Analy- 
sis (pp.  291-4).  It  was  found  necessary  to  digest  the  light 
oils  as  long  as  3  or  4  hours  and  the  heavy  ones  as  long  as  8 
hours  before  the  contents  of  the  digestion  flask  became  color- 
less. Another  necessary  precaution  had  to  be  observed  in 
applying  heat  very  gradually  to  the  flask  at  the  beginning  of 
the  digestion,  otherwise  the  nitrogenous  material  distilled  off, 


i8 

giving  results  that  were  far  below  those  obtained  when  greater 
precaution  was  exercised. 

Table  VII —  Nitrogen  Determinations 

Fraction  Sp.  gr.  Per  cent,  nitrogen 

2-A  t>.8264  0.08 

2-B  0.8421          0.116 

2-C  0.852  0.289 

2-D  0.8614  0-315 

2-B  0.8737  0.332 

Crude  oil  0.889  0.761 

These  results  show  that  the  proportion  of  nitrogen  com- 
pounds is  reduced  in  the  lightest  fraction  to  nearly  one  per 
cent,  of  its  total  amount.  This  proportion  of  nitrogen  was 
still  further  reduced  by  the  second  fractionation  of  the  two 
lightest  fractions.  The  fractions  obtained  from  2-A  are  desig- 
nated by  2-A  i,  2-A  2,  etc.  Those  from  2-B  are  designated 
by  2-B  i,  2-B  2,  etc. 

Table  VIII — Second  Fractionation  of  California  Oil  II 

Fraction  Sp.  gr.  Per  cent,  nitrogen 

2-A  i  0.8117  Trace 

2-A  2  0.8 1 86  Trace 

2-A  3  0.8193  0.03 

2-A  4  o .  8240  o .  06 

2-B  i  0.8205  Trace 

2-B  2  0.8386  0.045 

2-B  3  0.8414  0.09 

2-B  4  0.8421  o.  109 

From  the  above  results  it  is  apparent  that  the  fuller's  earth 
is  particularly  potent  in  selectively  absorbing  nitrogen  com- 
pounds from  the  oil.  In  view  of  the  fact  that  but  two  filtra- 
tions  through  the  earth  succeeded  in  reducing  the  amount  of 
nitrogen  present  to  such  a  small  proportion  as  compared  to 
that  in  the  petroleum,  it  is  probable  that  a  third  filtration 
would  have  reduced  it  to  zero.  A  third  fractionation  would 
have  been  made,  but  lack  of  workable  material  rendered  this 
impossible. 

The  analysis  of  the  oil  retained  by  the  earth  taken  from  the 


19 

upper,  middle  and  lower  ends  of  the  tubes  showed  that  the 
part  in  the  lowest  sections  of  the  tube  had  absorbed  the  great- 
est amount  of  the  nitrogen  compounds  from  the  petroleum. 
The  oil  was  extracted  from  sections  of  earth,  taken  at  differ- 
ent levels  from  the  tubes,  by  ether.  The  ether  was  evaporated 
off  in  an  electrical  drying  oven  at  50°. 

Table  IX — Analysis  of  Oil  Retained  by  Fuller's  Earth 

Section  of  tube  Sp.  gr.  Per  cent,  nitrogen 

Upper  end  o .  84 1 3  o .  205 

Middle  section  0.8655  °-43 

Lower  end  0.9172  0.94 

The  concentration  of  the  nitrogen  compounds  in  the  lower 
end  of  the  tubes  is  apparent.  It  is  noticeable  that  the  per- 
centage of  nitrogen  here  is  slightly  greater  than  it  was  in  the 
original  petroleum.  This  was  to  be  expected,  inasmuch  as 
the  earth  in  the  lower  end  of  the  tube  came  into  contact  with 
the  greatest  amount  of  oil  and  could  thus  selectively  absorb 
more  of  the  nitrogen  compounds  than  fcarth  in  the  upper  end. 
Moreover,  earth  in  the  upper  end  came  into  contact  with  oil 
that  had  already  had  a  portion  of  its  nitrogen  compounds  re- 
moved and  could  not,  for  that  reason,  extract  as  much  nitro- 
genous material  from  it  as  it  could  from  oil  that  was  much  richer 
in  nitrogen  compounds. 

The  study  of  the  benzene  and  olefin  hydrocarbons  in  Cali- 
fornia petroleum  was  next  contemplated.  Before  taking  this 
up,  it  was  considered  advisable  to  study  with  some  degree  of 
accuracy  the  behavior  of  known  mixtures  of  benzene  and  pure 
paraffin  oilwhere  such  mixtures  were  allowed  to  diffuse  through 
fuller's  earth.  This  problem  had  been  investigated  before 
by  earlier  workers  in  this  field,  and  certain  conclusions  arrived 
at,  but  a  further  study  of  the  same,  working  under  somewhat 
different  conditions,  was  now  resumed. 

FRACTIONATION   OF   MIXTURES   OF   BENZENE   AND   PARAFFIN   OIL 

In  previous  work  by  Gilpin,  Cram  and  Bransky  on  the  frac- 
tionation  of  crude  petroleum,  it  was  noted  that  there  was  a 
tendency  for  the  pure  paraffin  hydrocarbons  to  collect  in 


20 

the  upper  section  of  the  tube  through  which  the  petroleum 
was  allowed  to  diffuse.  To  investigate  this  more  closely, 
Gilpin  and  Bransky  studied  the  behavior  of  mixtures  of  ben- 
zene and  paraffin  oil,  such  mixtures  being  of  definitely  known 
composition,  and  plotted  their  results  in  curves  that  showed 
the  relative  amounts  of  benzene  and  paraffin  oil  that  collected 
in  all  parts  of  the  tube.  The  curves  show,  moreover,  that 
the  proportion  of  benzene  decreases  gradually  as  one  passes 
from  Grade  F  (the  oil  from  the  lowest  section  of  the  tubes)  to 
Grade  C  (the  oil  from  the  third  section  of  the  tubes),  Grade  A 
being  considered  that  fraction  from  the  uppermost  part  of 
the  tubes.  Above  Grade  C,  there  is  a  sharp  decrease  in  the 
proportion  of  benzene,  the  same  dropping  far  below  the  propor- 
tion in  the  original  mixture  that  was  put  into  the  reservoir. 
It  was  also  noted  that  the  curves  representing  the  specific 
gravities  of  the  various  sections  were  about  parallel  with  those 
representing  the  percentages  of  benzene.  This  was  to  be  ex- 
pected, since  the  benzene  was  of  considerably  higher  specific 
gravity  than  the  paraffin  oil.  The  tubes  employed  measured 
five  feet  six  inches  in  length. 

With  the  view  to  determine  more  accurately  the  exact  loca- 
tion of  the  break  in  the  curve,  and  to  ascertain  if  it  was  a  func- 
tion of  the  length  of  the  tube,  investigation  along  this  line 
was  begun  by  the  authors.  In  order  to  study  the  latter  prob- 
lem, it  was  decided  to  use  shorter  tubes,  those  of  two  feet 
nine  inches  in  length  being  chosen.  Correspondingly  smaller 
sections  of  earth  were  taken,  and  the  oil  was  displaced  from  them 
by  the  addition  of  water. 

The  benzene  used  was  of  specific  gravity  o .  879.  The  method 
of  analysis  used  to  determine  the  proportion  of  benzene  and 
paraffin  oil  in  each  fraction  consisted  in  shaking  10  cc.  of  the 
oil  with  three  or  four  times  its  volume  of  concentrated  sul- 
phuric acid,  until  all  of  the  benzene  had  been  sulphonated. 
Then  the  shaken  material  was  poured  into  a  burette  and  al- 
lowed to  stand  until  all  the  paraffin  oil  mechanically  held  in 
combination  with  the  acid  had  separated  out. 

To  determine  the  length  of  time  necessary  for  shaking  in 
order  to  remove  all  the  benzene,  10  cc.  of  benzene  were  mixed 


21 

with  an  equal  quantity  of  pure  paraffin  oil  and  the  mixture 
shaken  with  four  times  its  volume  of  concentrated  sulphuric 
acid  in  a  machine  that  agitated  the  mixture  about  450  times 
per  minute.  The  amounts  of  benzene  that  were  absorbed 
after  definite  periods  of  time  were  as  follows: 

Table  X  — A  ction  of  Sulphuric  A  cid  on  Benzene  and  Paraffin  Oil 

Time  of  shaking          .  Per  cent,  benzene 

Minutes  absorbed 

15  52.1 

30  79.0 

45  9i-4 

60  100. o 

All  samples  for  analysis  were,  therefore,  shaken  for  more 
than  an  hour,  until  further  shaking  failed  to  reduce  the  volume 
of  the  oil. 

The  paraffin  oil  used  was  a  light,  pale  yellow  oil  of  very 
disagreeable  odor.  Its  specific  gravity  was  0.7895  at  20°. 
After  purification  by  the  method  described  below,  the  specific 
gravity  became  0.7775.  The  oil  was  purified  as  follows:  A 
quantity  was  agitated  with  one-third  its  volume  of  concen- 
trated sulphuric  acid  for  6  hours  in  two  2 -liter  bottles  that  re- 
volved slowly  about  an  axis  placed  between  the  two.  The 
acid  became  dark  brown,  and  the  evolution  of  sulphur  dioxide 
indicated  chemical  action.  The  acid  was  then  drawn  off  in  a 
large  separatory  funnel  and  a  fresh  supply  added  to  the  oil. 
This  was  again  agitated  for  six  hours  and  separated  off  as  be- 
fore. By  this  process  the  volume  of  oil  decreased  9 . 3  per  cent., 
and  lost  its  disagreeable  odor  and  became  colorless.  It 
was  then  shaken  with  a  small  quantity  of  dilute  alkali  until 
neutral,  washed  with  water,  and  finally  shaken  for  several 
hours  with  calcium  chloride,  and  filtered.  By  repeated  tests 
it  was  shown  that  the  oil,  after  this  treatment,  did  not  de- 
crease in  volume  when  shaken  with  sulphuric  acid. 

Mixtures  of  benzene  and  pure  paraffin  oil  were  then  allowed 
to  diffuse  through  fuller's  earth.  The  earth  in  the  tubes  had 
been  as  tightly  packed  as  it  was  possible  to  secure  by  ramming 
the  earth  with  a  rod  tipped  with  a  rubber  stopper.  The  pro- 


22 


portions  of  benzene  and  paraffin  oil  in  the 

mixtures  were  as 

follows  : 

Name  applied 

Per  cent. 

Per  cent. 

to  mixture 

benzene 

paraffin  oil 

Series  No.    5 

2O 

80 

Series  No.    6 

33 

67 

Series  No.    7 

50 

50 

Series  No.    8 

75 

25 

Series  No.    9 

20 

80 

Series  No.  10 

33 

67 

Series  No.  n 

50 

50 

Series  No.  12 

20 

80 

Series  No.  13 

75 

25 

Series  No.  14 

20 

80 

Sections  of  varying  lengths,  as  shown  in  the  tables  accom- 
panying the  curves  (pp.  23  to  29),  were  taken,  and  the  oil  was 
displaced  by  addition  of  water  (in  Series  No.  5  to  No.  8,  inclu- 
sive), by  extraction  with  ether  (Series  No.  9),  or  by  letting  the 
oil  overflow  into  upper  reservoirs  by  the  new  method  described 
on  page  16  (Series  No.  14). 

The  sections  of  earth  from  which  the  oil  was  extracted  were 
made  considerably  smaller  than  similar  sections  taken  by 
Bransky  in  his  work.  The  uppermost  section,  called  A, 
varied  in  length  from  25  to  12  cm.  The  fraction  of  oil  that  it 
yielded  was  called  5~A,  6-A,  according  to  the  series  to  which 
it  belonged.  The  next  lower  section  of  earth,  usually  a  little 
shorter  than  A,  was  called  B.  Its  oil  was  termed  5-6,  6-B,  or 
7~B,  according  to  the  series  to  which  it  belonged.  The  short 
tube  and  short  sections  of  earth  from  which  the  oil  was  ex- 
tracted were  chosen  so  as  to  locate  more  accurately  the  point 
at  which  a  sharp  decrease  in  the  amount  of  benzene  occurred. 
This  point  of  sudden  change  was  found  to  be  invariably  loca- 
ted from  20  to  40  cm.  from  the  top.  The  specific  gravity  of 
each  fraction  of  the  oil  was  taken  for  the  first  five  tubes.  Since 
this  in  every  case  was  a  function  of  the  proportion  of  benzene 
and  paraffin  oil  present,  it  was  discontinued  after  the  first  five 
series  were  run. 

Series  No.  5  consisted  of  the  following:  A  tube  was  filled 
with  earth  and  the  reservoir  below  filled  with  500  cc.  of  a  mix- 


ture  of  20  per  cent,  of  benzene  of  specific  gravity  0.879  and 
80  per  cent,  of  paraffin  oil  of  specific  gravity  0.7775.  When 
diffusion  had  taken  place,  the  fractions  were  analyzed  as  before 
described,  and  it  was  found  that  the  break  in  the  curve  oc- 
curred at  about  35  cm.  from  the  top.  The  specific  gravity  of 
that  fraction  that  contained  least  benzene  was  the  lowest. 
It  was  noticeable  that  the  proportion  of  benzene  to  paraffin 
oil  was  nearly  a  constant,  until  the  point  B  was  reached  (see 
Fig.  I). 

Table  XI — Series  No.  5 

Benzene,  20  per  cent.  Paraffin  Oil,  80  per  cent. 

Rose  to  a  height  of  88  cm. 


Per  cent.       Per  cent. 

Fraction                     Cm.               Cc.                Sp.  gr.           benzene         paraffin 

5-A                  20          46          0.787         10.4         89.6 

5-B                   15           44           0.790         19.1         80.9 

5-C                   15           43           o-79i         21.3         78.7 

5-D                  15           36           0.792         21.0         79.0 

5-B                   12           30           0.792         21.3         78.7 

5-F                   ii           39           o. 

795         23.3         76.7 

A  - 

A 

\ 

\ 

B  <• 

\ 

\ 

B  - 

fc 

1 

O 

3 

£C" 

\ 

ID, 

\D 

\ 

* 

V 

/ 

E- 

E~ 

F- 

F  - 

i 

JO          20         3O         4O         $0           6O                                    JO          20          3O        4O        50          60 

Per  cent.  Benzene                                                      Per  cent.  Benzene 

Fig.  I.—  Series  No.  5                                             Fig.  II.—  Series  No.  6 

In  Series  No.  6  there  was  not  noticed  as  marked  uniformity 
in  specific  gravity  or  in  the  proportion  of  benzene  to  paraffin 
oil  as  in  Series  No.  5.  The  break  in  the  curve  occurred  about 
25  cm.  from  the  top  (see  Fig.  II) . 

Table  XII— Series  No.  6 

Benzene,  33  per  cent.  Paraffin  Oil,  67  per  cent. 

Rose  to  a  height  of  95  cm. 

Fractions 

6-A 
6-B 
6-C 
6-D 
6-B 
6-F 

Series  No.  7,  with  equal  quantities  of  benzene  and  paraffin 
oil,  gave  a  curve  that  broke  sharply  at  Section  B,  16  cm.  from 
the  top.  Up  to  this  point  the  amounts  of  the  two  oils  remained 
nearly  constant  (see  Fig.  III). 


A    '" 


Cm. 

Cc. 

Sp.  gr. 

Per  cent, 
benzene 

Per  cent, 
paraffin 

25 

31 

0.725 

18.4 

8l.6 

15 

38 

0.798 

25-7 

74-3 

15 

42 

0.798 

25-3 

74-7 

12 

38 

0.799 

25-9 

74.1 

12 

35 

0-7995 

27-3 

72.7 

12 

45 

0.799 

27.0 

73-o 

c 


r 

E 
F 


0         20  30          40          50 

Per  cent.  Benzene 
Fig.  III.— Series  No.  7 


60 


IO       20       3O        40      SO 

Per  cent.  Benzene 
Fig.  IV.— Series  No.  8 


60      70 


25 

Table  Xlll— Series  No.  7 

Benzene,  50  per  cent.  Paraffin  Oil,  50  per  cent. 

Rose  to  a  height  of  90  cm* 

Per  cent.       Per  cent. 
Fractions  Cm.  Cc.  Sp.  gr.  benzene         paraffin 

7-A  16  21  0.8023  30-5  69.5 

7-B  16  34  0.8155  47.0  53.0 

7-C  16  44  0.8160  45.8  54.2 

7-D  1 6  50  0.8165  45.7  54.3 

7-B  12  48  0.8165  45-7  54-3 

7-F  12  53  0.817  47.2  52.8 

In  Series  No.  8  the  break  was  not  such  a  sharp  one,  and  oc- 
curred about  30  cm.  from  the  top  (see  Fig.  IV). 

Table  XIV— Series  No.  8 

Benzene,  75  per  cent.  Paraffin  Oil,  25  per  cent. 

Rose  to  a  height  of  84  cm. 

Per  cent.       Per  cent. 
Fractions  Cm.  Cc.  Sp.  gr.  benzene         paraffin 

8-A  15  25  0.832  58.1  31.9 

8-B  15  37  0.833  64.5  35.5 

8-C  12  38  0.8385  69.0  31.0 

8-D  12  44  0.839  69.8  30.2 

8-E  12  43  0.839  69.7  30.3 

8-F  12  51  0.842  70.1  29.9 

In  order  to  determine  whether  the  proportion  of  benzene 
to  paraffin  oil  in  the  fractions  was  affected  by  the  displacement 
of  the  oil  by  water,  the  fractions  secured  from  Series  No.  9 
were  extracted  with  ether.  The  results  plotted  in  the  curve  on 
page  26  show  that  the  water  plays  no  part  whatever  in  the 
action.  The  break  in  the  curve,  showing  a  sudden  sharp  de- 
crease in  the  proportion  of  benzene  to  paraffin  oil,  occurred 
in  about  the  same  locality. 

Table  XV— Series  No.  9 

Benzene,  20  per  cent.  Paraffin  Oil,  80  per  cent. 

Rose  to  a  height  of  70  cm. 

Per  cent.  Per  cent. 

Fractions  Cm.  Cc.  benzene  paraffin 

9- A  12  44  8.9  91 .  i 

9-B  12  34  18.4  81.6 

9~C  12  38  20.0  80.0 

9-D  10  37  21.7  79.3 

9-E  10  39  21.3  79.3 

9-F  10  44  22.1  78.9 


26 

In  Series  No.  10  and  No.  n  (Figs.  VI  and  VII)  the  indi- 
vidual fractions  were  analyzed  immediately  after  the  displace- 
ment of  the  oil  in  the  earth  by  water.  This  was  done  so  as  to 
avoid  any  possible  loss  of  either  oil  by  evaporation.  The  same 
general  characteristics  are  apparent  in  the  curves  that  express 
the  results  of  the  fractionation. 


r 

E 
F 


10       20       30       40 
Per  cent.  Benzene 
Fig.  V.— Series  No.  9 


60 


IO         20          30         4O         $O         60 

Per  cent.  Benzene 
Fig.  VI.— Series  No.  10 


Table  XVI— Series  No.  10 

Benzene,  33  per  cent.  Paraffin  Oil,  67  per  cent. 

Rose  to  a  height  of  81  cm. 


Fractions 

Cm. 

Cc. 

Per  cent, 
benzene 

Per  cent, 
paraffin 

IO-A 

15 

36 

20.1 

79-9 

IO-B 

15 

53 

26.2 

73-68 

IO-C 

12 

45 

28.0 

72.0 

io-D 

12 

52 

27.7 

72.3 

lo-E 

12 

42 

28.1 

71.9 

io-F 

10 

37 

30-4 

69.6 

Table  XVII— Series  No.  n 

Benzene,  50  per  cent.  Paraffin  Oil,  50  per  cent. 

Rose  to  a  height  of  74  cm. 

Per  cent.  Per  cent. 

Fractions  Cm.  Cc.  benzene  paraffin 

ii-A  15  35  32.1     67.9 

n-B  12  42  47.1     52.9 

n-C  12  37  47.1 

n-D  ip  41  46.9 

n-E  10  36  50.4 

ii-F  10  35  50.9 


B   - 
C   - 

E 
F 


\ 


IO         20         3O         40  SO         6O 

Per  cent.  Benzene 
Fig.  VII.— Series  No.  11 


10 


52.9 

55-1 
49.6 
49.1 


20         3O         40 

Per  cent.  Benzene 
Fig.  VIII.— Series  No.  12 


50       60 


In  all  tubes  up  to  Series  No.  12  the  oil  was  drawn  up  to  a 
height  under  two  feet  nine  inches.  Although  tubes  five  feet 
nine  inches  long  were  used,  the  quantity  of  oil  placed  in  the 
reservoir  was  such  as  allowed  only  the  lower  half  of  the  earth 
in  the  tube  to  become  impregnated.  In  order  to  avoid  the 
possibility  of  the  more  volatile  oil  evaporating  into  the  dry  earth 
above  it,  tubes  of  2  feet  9  inches  in  length  were  used  for  Series 
No.  12  and  No.  13.  The  curves  representing  the  results  from 


28 

these  series  (pp.  27  and  29)  show  that  this  precaution  failed 
to  produce  any  noticeable  difference  in  the  proportion  of  ben- 
zene and  paraffin  oil  or  in  the  characteristic  behavior  of  the 
fractions  that  were  obtained  by  diffusion  through  fuller's 
earth. 

Table  XV III— Series   No.   12 

Benzene,  20  per  cent.  Paraffin  Oil,  80  per  cent. 

Rose  to  a  height  of  80  cm. 

Per  cent.  Per  cent. 

Fractions  Cm.  Cc.  benzene  paraffin 

I2-A  15  31  9.5  90.5 

I2-B  15  40  16.8  83.3 

I2-C  12  54  18.6  81.4 

I2-D  12  52  18.8  81.2 

I2-E  12  56  18.0  82.0 

I2-F  12  53  21. i  79.9 


Table  -XIX— Series  No.  13 

Benzene,  75  per  cent.  Paraffin  Oil,  25  per  cent. 

Rose  to  a  height  of  80 . 5  cm. 

Per  cent.  Per  cent. 

Fractions  Cm.  Cc.  benzene  paraffin 

I3-A  15  30  60.0  40.0 

I3-B  15  41  69.1  31.9 

I3-C  12  37  72.8  27.2 

1 3-D  12  41  71.3  28.7 

I3~B  12  47  74.0  26.0 

I3-F  12  48  74.9  25.1 


Series  No.  14  was  set  up  to  test  out  the  improved  method 
of  fractionating  by  means  of  the  earth.  Eight  hundred  cc. 
of  a  mixture  of  20  per  cent,  benzene  and  80  per  cent,  paraffin 
oil  were  drawn  up  through  tightly  packed  fuller's  earth,  and 
six  fractions  of  50  cc.  each  were  collected  in  the  upper  reser- 
voir. The  first  of  these  was  designated  i4~A,  and  the  last  i4~F. 
The  six  fractions  were  separately  analyzed  and  the  results 
plotted  in  a  curve  (see  p.  29). 


29 


2nd 

} 

A 

B 

»> 

I 

jc 

§ 

t, 

*  D 

• 

1 

\             5th 

i5  E  ' 

, 

F 

6th 

\ 

IO      20      JO       40      50      60        70                                         10          20          30           40        50          60 

Per  cent.  Benzene                                                        Per  cent. 

Benzene 

Fig.  IX.  —  Series  No.  13                                          Fig.  X.  —  Series  No.  14 

Table  XX—  Series  No.  14 

Benzene,  20  per  cent.              Paraffin  Oil,  80 

per  cent. 

Per  cent. 

Per  cent. 

Fractions                            Cc.                           benzene 

paraffin 

I4-A                      50                    10.9        t 

89.I 

I4-B                       50                     17.1 

82.9 

I4-C                       50                     19.4 

80.6 

I4-D                      50                     21.6 

78.4 

I4-E                      50                     23.0 

77-0 

I4-F                      50                    20.0 

80.0 

Extract  of  Earth  Left  in  Tube 

Per  cent. 

Per  cent. 

Fractions                       Cm.                     Cc.                 benzene 

paraffin 

Upper  half            70              215            15.9 

84.1 

Lower  half            70              225            13.8 

86.2 

It  was  found  that  the  proportion  of  benzene  in  the  first 
fraction  was  the  lowest,  and  that  it  gradually  increased  in 
the  subsequent  fractions.  The  curve  above  shows  that 
the  increase  in  benzene  in  the  successive  fractions  is  more 


30 

gradual  than  when  the  oil  was  obtained  by  being  expelled  by 
water.  There  was,  however,  a  marked  increase  in  the  amount 
of  the  benzene  after  the  first  50  cc.  had  been  drawn  off.  This 
corresponds  to  the  increase  indicated  by  the  curves  in  every 
series  that  was  run,  and  thus  it  appears  that  the  new  method 
of  working  gives  the  same  results  as  the  other  methods  of 
manipulation. 

These  results  show  that  the  degree  of  fractionation  is  not  a 
question  of  the  absolute  height  of  the  earth  through  which 
the  oil  passes,  but  of  the  relative  height.  The  advantage, 
however,  of  using  long  tubes  is  that  more  material  can  be 
obtained  and  a  greater  number  of  fractions  between  the  two 
extremes  are  possible. 

FRACTIONATION   OF   CALIFORNIA   OIL  III 

With  a  view  to  studying  in  some  detail  the  fractionation 
of  a  heavy  California  petroleum,  a  tank  of  this  material  was  se- 
cured from  Kern  County.  It  had  a  specific  gravity  of  0.9118 
at  20°,  and  resembled  in  physical  properties  the  California 
Oil  I.  A  description  of  this  oil,  termed  California  Oil  III,  is 
found  on  page  6.  In  order  to  find  the  best  conditions  for  se- 
curing large  workable  fractions  of  this  oil,  preliminary  work 
was  carried  on  by  means  of  glass  tubes  so  as  to  enable  the  in- 
vestigator to  observe  the  progress  of  the  fractionation.  The 
glass  tubes  measured  1.25  inches  in  internal  diameter,  and 
varied  in  length  from  two  to  five  feet.  The  object  of  this  was 
to  find  the  length  of  tube  which  would  give  a  maximum  yield 
of  workable  fractions. 

The  tubes  were  filled  with  a  fine-grained  fuller's  earth  known 
as  XXF  clay.  The  method  of  packing  these  by  ramming 
with  a  rod  tipped  with  a  rubber  stopper  was  abandoned  since 
this  gave  varying  degrees  of  hardness,  while  strict  uniformity 
was  desired.  It  also  failed  to  remove  the  cushions  of  air  that 
persisted  in  remaining  between  layers  of  the  earth,  and  these,, 
it  had  been  found  in  earlier  work,  were  a  grave  source  of 
trouble.  Instead,  the  earth  was  run  into  the  tubes  until  they 
were  full.  Then  the  tubes  were  tapped  on  their  sides  through- 
out their  length  until  the  earth  failed  to  subside.  More  earth 


was  added  to  fill  in  the  space  left  vacant  by  the  earth  that  had 
settled,  and  they  were  tapped  again  until  further  subsidence 
ceased. 

With  tubes  packed  as  indicated  above,  the  fractionation 
of  the  oil  by  suction  was  commenced.  It  was  soon  apparent 
that  the  amount  of  fractionation  by  using  the  fine-grained 
earth  would  be  exceedingly  small,  and  that  it  would  possibly 
require  four  or  five  weeks'  suction  to  bring  the  oil  to  the  top 
of  the  longer  tubes,  so  the  effect  of  using  a  coarse-grained 
earth  was  suggested.  Accordingly,  fuller's  earth  of  the  size 
30  to  60  mesh  was  secured.  The  tubes  were  packed  uniformly 
by  the  method  above  described,  and  placed  in  the  reservoirs. 
The  pressure  was  reduced  to  650  mm.  of  mercury.  Even  at 
this  slight  reduction  in  pressure,  the  oil  was  drawn  up  through 
the  tubes,  the  products  showing,  however,  no  signs  of  frac- 
tionation. Accordingly,  after  repeated  experiments,  the  tubes 
were  allowed  to  stand  48  hours  with  no  suction  applied,  and 
then  the  pressure  on  the  top  of  the  tubes  was  reduced  to  730 
mm.  With  this,  the  oil  started  to  rise  slowly  and  steadily 
through  the  earth,  the  uppermost  part  showing  signs  of  marked 
fractionation.  When  the  oil  had  risen  to  the  height  of  about 
1 8  inches,  the  pressure  was  reduced  to  700  mm. ;  at  a  height  of 
3  feet,  it  was  reduced  to  650  mm. ;  and  above  4 . 5  feet  it  was 
maintained  at  600  mm.  until  all  of  the  available  oil  was  drawn 
over  into  the  upper  reservoirs.  By  use  of  the  coarse-grained 
fuller's  earth  the  time  required  for  fractionation  of  a  series  of 
tubes  was  found  to  be  from  ten  to  twelve  days.  The  frac- 
tions of  oil  that  were  drawn  up  and  collected  were  classified  on 
the  basis  of  color.  With  this  as  a  criterion,  six  distinctly 
different  fractions  were  obtained,  and  these  showed  a  wide 
range  in  color  and  specific  gravity. 

The  total  amount  of  these  six  fractions  was,  however,  only 
15  per  cent,  of  the  oil  put  into  the  lower  reservoir,  there  being 
a  loss  of  85  per  cent,  due  to  the  speedy  darkening  of  the  earth 
by  the  bitumen  present  in  the  petroleum.  Results,  with  a 
brief  description  of  the  fractions  obtained,  are  tabulated  be- 
low: 


32 
Table  XXI — Preliminary  Fractionation  of   California   Oil   111 

Fraction  Sp.  gr.  Description 

1  0.8364          Nearly  colorless;  pale  green  fluor- 

escence 

2  0.8449          Pale  yellow;  pale    green    fluor- 

escence 

3  0.8609          Yellow;  quite  fluorescent 

4  0.8701  Light  brown;  strong  fluorescence 

5  0.8770  Brown;  strongly  fluorescent 

6  0.8866  Dark  brown;  deep    green    fluor- 

escence 

These  were  the  first  results  that  were  ever  obtained  with  an 
oil  of  as  high  specific  gravity  and  viscosity  as  this  one,  for  all 
investigations  carried  on  at  room  temperature  with  an  oil 
of  this  high  density  had  failed  thus  far  to  produce  any  results. 
When  these  six  fractions  were  next  examined  as  to  their  chem- 
ical properties,  it  was  found  that  the  diffusion  through  the 
earth  had  not  only  lowered  the  viscosity  of  the  oil,  removed 
the  bitumen,  and  thereby  greatly  decreased  the  specific  grav- 
ity of  the  oil,  but  it  had  also  absorbed  from  the  petroleum  a 
large  proportion  of  benzene  and  olefin  hydrocarbons. 

The  amounts  of  the  two  last-named  ingredients  were  ascer- 
tained by  treatment  of  the  oil  with  concentrated  sulphuric 
acid.  This  did  not  determine  the  benzene  and  olefin  hydro- 
carbons separately.  It  is  fair  to  assume  that  the  concentrated 
acid  acted  upon  the  other  materials  in  the  oil,  but  that  it 
removed  all  the  benzene  and  olefin  hydrocarbons  was  conclu- 
sively proved  by  a  method  described  later  on. 

The  method  by  which  the  benzenes  plus  the  olefins  were  de- 
termined was  as  follows:  Ten  cc.  of  each  fraction  were  care- 
fully measured  from  a  burette.  The  light  oils  were  shaken 
with  three  times  their  volume  of  concentrated  sulphuric  acid 
until  no  further  diminution  in  the  volume  of  the  oil  occurred. 
The  shaking  was  accomplished  in  a  machine  that  vibrated  400 
times  per  minute.  The  bottles  containing  the  oil  thus  treated 
were  emptied  into  burettes,  rinsed  with  a  few  cc.  of  acid  and 
allowed  to  drain  overnight.  The  oil  not  acted  upon  rose  in 
this  time  above  the  acid,  and  could  be  read  off  and  directly 
translated  into  percentages  of  paraffin  hydrocarbons  present. 


33 

This  last  statement  is  based  upon  the  fact  that  paraffin  hydro- 
carbons are  not  acted  upon  by  cold,  concentrated  sulphuric 
acid,  while  the  benzene  and  olefin  hydrocarbons  react  with 
the  acid  to  form  sulphonic  and  alkylsulphuric  acids,  respect- 
ively. That  the  benzene  and  olefin  hydrocarbons  were  en- 
tirely removed  by  two  hours'  agitation  with  a  large  excess 
of  sulphuric  acid  was  proved  by  the  absence  of  these  com- 
pounds in  the  oil  after  it  had  been  acted  upon.  The  test  for 
benzene  was  the  action  of  nitric  acid  to  give  nitro  derivatives 
and  the  subsequent  reduction  to  give  amino  compounds. 
The  tests  for  olefin  were  the  direct  addition  of  bromine  and  the 
action  of  alkaline  permanganate  solution. 

The  treatment  of  the  heavier  oils  with  sulphuric  acid  was 
somewhat  different  from  that  of  the  light  oils,  in  that  in  the 
case  of  the  former  the  action  of  the  acid  produced  a  mixture 
so  dark  and  viscous  that  the  line  of  demarcation  between  the 
acid  and  the  unabsorbed  oil  was  invisible.  Therefore,  the  sam- 
ple of  heavy  oil  was  treated  in  one  of  the  following  ways: 

I.  It  was  mixed  with  twice  its  volume  of  pure  paraffin  oil 
that  had  been  treated  previously  with  concentrated  acid  until 
none  of  it  was  absorbed  by  further  action  of  the  acid  upon  it 
(see  p.   21).     The  diluted  oil  was  then  shaken  for  five  hours 
or  more  with  three  times  its   volume   of   acid   until    further 
diminution  in  volume  of  the  oil  ceased;1  or 

II.  The  sample  was  shaken  with  thirty  cc.  of  sulphuric  acid 
for  two  hours,  and  the  mixture  was  thinned  out  by  diluting 
with  twenty  cc.  of  the  paraffin  oil,  shaken  for  a  few  minutes, 
drained  into  the  burette,  and  the  amount  of  benzenes  and 
olefins  present   determined  by  difference   between   thirty  cc. 
and  the  amount  of  oil  unabsorbed  by  the  acid.     The  methods 
of   determining   the   sulphuric   acid   absorption   gave   results 
that  were  concordant  to  within  0.5  per  cent.     The  accuracy 
of  the  analysis  by  this  method  was  within  one  per  cent.,  as  was 
proved  by  analysis  of  known  mixtures. 

The  percentages  of  benzene  and  olefin  hydrocarbons  that 

1  For  diluting  the  10  cc.  sample  for  analysis  and  shaking  with  90  cc.  of  sulphuric 
acid,  it  was  necessary  to  have  a  burette  of  over  120  cc.  capacity.  This  was  secured  by 
blowing  a  bulb  of  80  cc.  at  the  lower  end  of  a  50  cc.  burette,  leaving  a  volume  of  about 
40  cc.  above  by  which  to  read  the  amount  of  oil  that  was  not  acted  upon. 


34 

were  found  in  the  various  fractions  of  the  oil  (see  p.  32)  were 
found  to  vary  from  5. 15  per  cent,  to  27.7  per  cent.,  as  shown 
in  the  following  table : 

Table  XXII — Preliminary  Determination  of  Benzenes  and  Ole- 
fins  in  California  Oil  III 

Per  cent,  benzenes 
Fractions  and  olefins 

1  5-15 

2  10-4 

3  15-2 

4  16.8 

5  20.6 

6  27.7 

It  is  thus  seen  that  the  earth  through  which  the  oil  passed 
exerted  an  absorptive  effect  upon  the  benzene  and  olefin 
hydrocarbons.  This  effect  has  been  termed  selective  absorp- 
tion or  adsorption,  by  which  is  meant  that  the  earth  exerts 
an  action  upon  the  complex  oil  by  which  it  retains  an  apprecia- 
ble quantity  of  certain  of  its  ingredients.  It  is  not  a  filtration 
effect,  for  when  the  petroleum  is  drawn  quickly  through 
coarse  or  fine  fuller's  earth  by  means  of  low  pressure,  it  filters 
through,  depositing  any  solid  matter  that  may  be  suspended, 
but  being  otherwise  unaltered. 

If  the  action  of  the  earth  is  explained  as  a  phenomenon 
of  adsorption,  the  statement  might  be  made  that  the  separa- 
tion of  the  bituminous  material  from  the  petroleum  was  by 
the  coagulation  and  adhesion  of  the  bitumen  to  the  very  ex- 
tensive internal  surface  that  the  grains  of  fuller's  earth  pos- 
sess. For  it  is  a  well-known  fact  that  porous  media  like  char- 
coal, dried  clays,  colloidal  and  finely  divided  metals,  platinum 
sponge,  etc.,  possess  an  enormous  amount  of  surface  energy, 
due  to  the  forces  that  are  active  at  their  extensive  surface, 
and  that  such  substances  show  the  phenomenon  of  adsorption 
to  a  marked  degree.  The  separation  of  the  bitumen,  carry- 
ing with  it  the  benzene  hydrocarbons,  the  olefins,  the  sulphur 
and  nitrogen  compounds,  may  thus  be  regarded  as  a  special 
case  of  adsorption. 


35 

If  the  bitumen  is  considered  as  existing  in  the  colloidal  con- 
dition, the  effect  of  the  internal  surface  of  the  fuller's  earth 
could  be  explained  as  bringing  about  the  coagulation  of  the 
colloidal  bitumen  into  discrete  particles  which  would  carry 
with  them  all  materials  in  the  oil,  save  the  paraffin  hydrocar- 
bons. That  all  the  above-mentioned  materials  are  held  be- 
hind by  the  fuller's  earth  has  been  conclusively  established 
by  direct  and  indirect  proof.  In  retaining  the  bitumen  with 
benzenes,  olefins,  nitrogen  and  sulphur  compounds  and  per- 
mitting the  paraffin  oils  to  diffuse  through,  the  fuller's  earth  acts 
as  a  dialyzer,  proving  more  or  less  impervious  to  the  substances 
held  in  solution  in  the  paraffin  oils,  but  not  so  to  the  solvent 
itself. 

Fractionation  of  California  Oil  III 

For  the  more  accurate  study  of  the  physical  and  chemical 
properties  of  the  fractions  obtained  from  this  oil,  large  quan- 
tities of  these  fractions  were  necessary.  Accordingly,  a  slight 
alteration  was  made  in  the  apparatus  employed,  so  as  to  be 
able  to  handle  larger  quantities.  The  tubes  originally  used 
measured  1.25  inches  by  5.5  feet.  It  was  now  decided  to 
test  out  tubes  of  greater  diameter  and  length,  and  the  size 
finally  adopted  was  2.75  inches  in  diameter  by  six  feet  in 
length.  In  order  to  be  able  to  observe  the  behavior  of  the 
oil,  a  glass  tube  of  the  same  size  was  joined  in  parallel  with 
the  tin  tubes.  With  tubes  of  this  diameter  it  was  found 
that  the  best  results  were  obtained  by  using  very  little  suc- 
tion, and  by  extending  the  suction  over  a  period  of  about 
two  weeks,  as  the  yield  of  available  fractions  was  found  to 
increase  through  this  method  of  working.  This  was  ascer- 
tained by  measuring  the  amounts  of  each  of  the  fractions 
that  were  obtained  from  a  single  tube  placed  in  a  measured 
amount  of  petroleum.  From  this  tube  14  distinct  fractions 
were  secured,  the  basis  of  distinction  being  the  color  of  each. 
The  amounts  of  each  fraction  and  a  brief  description  of  the 
same  are  as  follows: 


36 
Table  XXIII — Preliminary  Fractionation   of  California  OH  111 

Amount 
Fraction         Cc.  Description 

1  35  Colorless,  pale  blue  fluorescence 

2  38  Colorless,  pale  green  fluorescence 

3  40  Pale  yellow,  pale  green  fluorescence 

4  40  Yellow,  pale  green  fluorescence 

5  48 

6  45         Yellow  to  deep  orange-brown,    increasing 

7  47  green   fluorescence  as  fractions  increased 


8  60 

9  65 

10  63 

11  75 

12  85 

13  88 

14  no 


in  sp.  gr.  and  viscosity 


Light  to  dark  brown  in  transmitted  light; 
fluorescence  less  pronounced,  but  still 
very  noticeable 


The  total  amount  of  available  fractions  was  839  cc.  The 
amount  of  petroleum  used  was  3500  cc.  The  yield  was  23.7 
per  cent. 

It  is  seen  from  the  above  figures  that  the  yield  of  heavier 
fractions  is  increasingly  greater  than  that  of  the  lighter  oils. 
It  is  also  to  be  noted  that  this  slower  method  of  working  in- 
creased the  total  yield  of  available  fractions  from  15  per  cent* 
to  nearly  24  per  cent.  Fractions  that  were  colored  darker 
than  the  fourteenth  were  discarded  as  being  contaminated 
with  too  much  bitumen. 

The  fractionation  of  considerable  quantities  of  California  Oil 
III  was  then  undertaken,  and  differentiation  was  made  be- 
tween the  various  fractions  on  the  basis  of  specific  gravity,  a 
hydrometer  small  enough  to  fit  into  the  upper  reservoirs 
being  used1  to  indicate  the  specific  gravity  approximately. 
The  boiling  points  of  the  various  fractions  were  taken  at 
atmospheric  pressure.  Every  fraction  was  found  to  be  a  mix- 
ture of  oils,  for  not  any  of  the  boiling  points  remained  con- 
stant, but,  instead,  rose  through  a  range  of  n  to  35  degrees. 
In  determining  the  boiling  points,  5  cc.  of  each  fraction  were 
taken.  In  order  to  get  the  boiling  point  of  the  greatest  part 

1  The  upper  reservoirs  were  glass  tubes  2.5  cm.  X  16.5  cm.  closed  at  one  end. 
Two-hole  rubber  stoppers  6tted  in  the  tops  which  were  flanged  slightly  to  give  air- 
tight connections. 


37 

of  each,  i.  e.,  of  that  part  which  represented  the  average  of 
the  constituents,  one  cc.  was  distilled  off,  and  the  boiling  point 
noted  during  the  distillation  of  the  next  three  cc.  The  boiling 
point  of  the  last  cc.  was  not  taken.  The  distillates  ranged 
from  a  colorless,  thin  oil  with  a  smoky  smell  to  a  thick,  dark 
brown  oil  of  a  very  disagreeable  odor  resembling  garlic. 

The  fractions  from  the  California  Oil  III  were  termed  3~A, 
3— B,  etc.  Those  of  a  second  frac donation  were  termed  3— A  i, 
3- A  2,  etc.  The  range  of  the  fractions  obtained  was  as  fol- 
lows: 

Table  XXIV—Fractionation  of  California  Oil  III 

Fraction  Sp.  gr.  Boiling  point 

1  3-A  0.8325  i6o°-i95° 

2  3-B  0.8347  I72°-20I° 

3  3-C  0.8372  i86°-2i9° 

4  3-D  0.8462  2io°-23i° 

5  3-E  0.8524  235°-26o0 

6  3-F  0.8551  247°-269° 

7  3-G  0.8680  256°-28o° 

8  3-H  0.8781  268°-289° 

9  3-1  0.8840  275°-3io° 

10  3-J  0.8885  284°-3i7° 

11  3-K  0.8903  299°-326° 

12  3-L  0.895  3ii°-328° 

13  3-M  0.8972  3i7°-334° 

14  3-N  0.8984  329°-34o0 
Crude  petroleum  0.9118  105  °~34O  ° 

These^results  show  the  very  wide  range  in  specific  gravity 
between  the  first  and  last  fractions  of  the  petroleum  under  in- 
vestigation. For  comparison,  the  range  of  fractions  obtained 
from  a  lighter  Pennsylvania  petroleum  by  Gilpin  and  Bransky 
are  given  in  the  following  table: 

Fractionation  of  Pennsylvania  Petroleum 

Fraction  Sp.  gr.  Fraction  Sp.  gr. 

A-i  0.8250  D-2  0.8495 

A-2  0.8287  D-3  0.8515 

B-i  0.8367  D-4  0.8555 

B-2  0.8392  E-i  0.8527 

C-i  0.8413  E-2  0.8540 

C-2  0.8460  E-3  0.8570 

C-3  0.8488 

D-i  o .  8470 


OQ 
5000000 

Specific  Gravity 
Fig.  XI. — California  Oil  III 


JO          20          30  40  50 

Per  cent.  Benzenes  +  Ole  fines 

Fig.   XII. — Sulphuric   Acid   Absorption   of   Cali- 
fornia Oil  III 


The  range  obtained  by  Bransky's  method  of  working  shows 
specific  gravities  varying  from  0.8250  to  0.8570,  as  contrasted 
with  the  range  of  0.8325  to  0.8984  obtained  by  the  present 
investigator  upon  the  heavy  California  oil. 

Sulphuric  Acid  Absorption  of  the  California  Oil  111 
The  sulphuric  acid  absorption  was  determined  for  the  four- 
teen fractions.  The  method  used  was  that  described  on 
pages  32  to  33.  The  results  are  tabulated  with  respect  to  the 
percentage  of  paraffin  hydrocarbons  in  contrast  to  that  of  the 
benzene  and  olefin  hydrocarbons  taken  together. 

These  figures  show  the  great  extent  to  which  the  diffusion 
through  fuller's  earth  removes  the  benzene  and  olefin  hydro- 
carbons. The  first  fraction  consisted  of  nearly  pure  paraffin 
oils,  reaching  a  degree  of  purity  of  96  per  cent.,  while,  by 
contrast,  the  crude  petroleum  contained  about  50  per  cent, 
of  paraffins. 


39 

'. 

Table  XXV — Sulphuric  Acid  Absorption 

Per  cent,  benzenes  Per  cent. 

Fraction  and  olefins  paraffins 

3-A  3-7  96.3 

3-B  4.14  95.86 

3-C  5-i  94-9 

3-D  7.44  92.56 

3-E  10.13  89.87 

3-F  13.06  86.94 

3-G  15.2  84.8 

3-H  15.8  84.2 

3-!  19-89  80. i i 

3-J  20.6  79.4 

3-K  23.47  76.53 

3-L  27.9  72.1 

3~M  31-45  68.55 

3-N  32.72  67.28 

Crude  petroleum    49 . 7  50 . 3 

Bromine  Absorption  of  California  Oil  HI 

In  order  to  determine  the  amount  of  unsaturated  or  olefin 
hydrocarbons  in  the  fourteen  fractions  of  this  oil,  the  quan- 
tity of  bromine  absorbed  at  room  temperature  (i9°-23°) 
in  the  dark  by  a  weighed  amount  of  the  oil  was  determined. 

The  method  employed  for  the  determination  of  the  olefin 
content  of  the  fractions  was  as  follows:  A  weighed  sample 
of  the  oil  to  be  analyzed,  about  0.6  gram  for  each  determina- 
tion, was  dissolved  in  fifteen  cc.  of  redistilled  carbon  tetra- 
chloride.  The  vessel  into  which  the  solution  was  introduced 
was  a  250  cc.  Erlenmeyer  flask  with  a  ground  glass  stopper 
that  fitted  accurately  and  was  sunk  some  distance  into  the 
neck  of  the  flask  so  as  to  leave  a  gutter  between  the  neck  and 
the  stopper.  When  the  absorption  of  bromine  was  taking 
place,  the  gutter  was  filled  with  a  couple  of  cc.  of  potassium 
iodide.  It  effectually  prevented  the  escape  of  bromine  vapor. 
The  bromine  was  introduced  in  the  form  of  a  solution  in  pure 
carbon  tetrachloride.  The  solution  was  made  practically 
decinormal  by  dissolving  3.3  cc.  of  redistilled  bromine  in  a  liter 
of  solvent.  Its  exact  strength  was  determined  by  titrating 
against  a  known  volume  of  a  standard  sodium  thiosulphate 


4o 

solution.  The  bromine  solution  kept  best  in  the  dark,  but 
frequent  tests  of  its  strength  were  necessary. 

In  determining  the  bromine  absorption,  a  known  quantity 
of  the  bromine  solution  was  added  to  the  solution  of  the  oil 
in  carbon  tetrachloride.  The  amount  added  was  more  than 
twice  that  necessary  to  combine  with  the  total  amount  of 
olefins  present  (as  determined  by  a  previous  analysis).  The 
flask  was  closed  and  shaken,  the  gutter  filled  with  2  cc.  of  a 
ten  per  cent,  solution  of  potassium  iodide,  and  the  flask  al- 
lowed to  stand  in  the  dark  with  occasional  agitating  for  thirty 
minutes.  Longer  contact  of  the  oil  with  the  bromine  gave 
substitution  products  as  well  as  addition  products,  the  former 
being  indicated  by  the  presence  of  hydrobromic  acid.  After 
thirty  minutes,  the  flask  was  brought  out  of  the  dark,  ten  cc. 
of  the  potassium  iodide  solution  were  added,  the  flask  closed 
and  violently  shaken,  and  the  amount  of  iodine  liberated 
by  the  excess  of  bromine  present  determined Jby  titrating  against 
the  thiosulphate  solution.  Toward  the  end  of  the  titration, 
a  few  cc.  of  a  very  dilute  starch  solution  were  added  to  indi- 
cate sharply  the  end  point.  Repeated  shaking  of  the  con- 
tents of  the  flask  was  necessary  during  the  last  part  of  the  titra- 
tion in  order  to  free  the  iodine  from  its  solution  in  the  carbon 
tetrachloride.  A  blank  determination  was  made  parallel 
with  each  analysis  in  order  to  ascertain  how  much  of  the  thio- 
sulphate solution  was  exactly  equivalent  to  the  amount  of 
bromine  solution  that  was  added.  The  results  were  trans- 
lated directly  into  the  percentage  of  olefins  present  in  the 
various  fractions  and  in  the  crude  petroleum. 

By  the  action  of  concentrated  sulphuric  acid  on  the  oils, 
the  percentage  of  benzenes  and  olefins  together  was  ascer- 
tained. The  action  of  bromine  gave  the  percentage  of  ole- 
fins. In  order  to  determine  whether  the  difference  between 
these  results  gave  a  value  that  represented  the  percentages  of 
benzene  alone,  an  investigation  was  carried  out  on  the  ist, 
5th,  Qth  and  i4th  fractions  of  the  California  Oil  III.  After 
being  shaken  for  several  hours  with  sulphuric  acid,  they  were 
tested  for  the  presence  of  benzenes  and  olefins,  and  blank 


41 

results  were  obtained.  Then  fresh  samples  of  these  fractions 
were  treated  with  an  excess  of  bromine  so  as  to  brominate 
the  olefins  present,  washed  with  water,  dried  and  shaken  with 
concentrated  sulphuric  acid  for  several  hours.  By  this, 
an  amount  of  the  oil  was  absorbed  which  corresponded  to  the 
benzenes  present.  This  amount,  added  to  that  secured  by 
the  action  of  bromine,  gave  the  true  percentages  of  benzenes 
and  olefins  together.  The  results,  however,  were  in  each  case 
a  little  high,  showing  that  the  sulphuric  acid  must  have  acted 
upon  the  brominated  oils,  but  the  difference  was  not  greater 
than  i .  3  per  cent.  Since  the  sulphuric  acid  absorption  method 
was  accurate  to  within  one  per  cent.,  it  was  concluded  that 
the  difference  between  the  percentages  of  the  oil  absorbed 
by  sulphuric  acid  and  that  acted  upon  by  bromine  could  be 
taken  to  represent  the  amount  of  benzene  hydrocarbons 
present. 

The  results  that  justified  this  conclusion  are  here  given: 

Table  XXVI 

Per  cent,  benzenes 

and  olefins  by 

Per  cent.  Per  cent.  Sum  of  sulphuric  acid  ab- 

Fraction      •  benzenes  olefins      columns  2  and  3    sorption 

3-A 

3-E 

3-1 

3-N 

In  the  table  below,  the  percentages  of  the  various  hydro- 
carbons present  in  the  oils  investigated  are  given.  In  the  first 
column  are  given  the  designations  of  the  various  fractions; 
in  the  second  are  given  the  mean  values  of  the  percentages 
of  the  olefins  found  by  determining  the  bromine  absorption 
(duplicate  determinations  made  in  every  analysis) ;  in  the  third 
are  given  the  percentages  of  benzenes  and  olefins  taken  to- 
gether, and  determined  by.  the  sulphuric  acid  absorption 
method;  in  the  fourth  are  given  the  percentages  of  benzenes  de- 
termined by  difference  between  the  second  and  third  columns. 

These  results  demonstrate  the  selective  absorption  of  the 
fuller's  earth  in  its  action  upon  the  olefin  hydrocarbons.  As  is 
indicated  above,  the  proportion  of  olefins  in  the  crude  oil  is 


1.09 

2.79 

3-88 

3-7 

5-35 

5-05 

10.4 

10.13 

8.72 

12.46 

21.  18 

19.89 

14.03 

19-35 

33-38 

32.72 

Table  XXV  11  —  Proportion    of  Various  Hydrocarbons  in  Frac- 

lions  of  California 

Oil  111 

Per  cent. 

Per  cent,  ben- 

Per cent. 

Fraction 

olefins 

zenes  and  olefins 

benzenes 

3-A 

2\79 

3-7 

0.8l 

3-B 

3-25 

4.14 

0.76 

3-C 

3-62 

5-i 

1.48 

3-D 

4.06 

*-44 

3-38 

3-B 

5-05 

10.13 

5.08 

3-F 

5.84 

13.06 

7.22 

3-G 

7-44 

15.2 

7.76 

3-H 

8-43 

18.8 

7-37 

3-1 

12.46 

19.89 

7-43 

3-J 

13-44 

20.6 

7.16 

3-K 

14.66 

23-47 

8.81 

3-L 

14.81 

27.9 

I3-I9 

3-M 

18.34 

31-45 

13.11 

3-N 

19-35 

32.72 

J3-37 

Crude 

petroleum    28  .  24 

49-7 

21.47 

3       6      Q     12   15   18  21 

Per  cent.  Olefines 
Fig.  XIII.— California  Oil  III 


24   27 


5  JO  15 

Per  cent.  Benzenes 
Fig.  XIV.— California  Oil  III 


43 

28.24  per  cent.  In  a  single  fractionation  this  is  reduced  to 
2 . 79  per  cent,  in  the  first  fraction  obtained.  The  gradual  in- 
crease in  the  proportion  of  olefins  as  the  specific  gravity  of 
the  fractions  increases  is  parallel  to  the  gradual  increase, 
in  successive  fractions,  of  all  the  compounds  in  the  petroleum 
thus  far  studied,  i.  e.,  of  the  sulphur  compounds,  nitrogen 
compounds,  benzene  hydrocarbons  and  olefin  hydrocarbons. 
The  results,  when  plotted  in  the  form  of  curves,  show  that  there 
is  a  noticeable  parallelism  in  selective  action  of  the  fuller's 
earth  upon  the  compounds  above  mentioned.  The  curves 
are  found  on  pages  38  and  42. 

In  order  to  determine  to  what  extent  the  olefins  could  be 
removed  by  further  filtration  through  fuller's  earth,  a  liter 
of  Fraction  3-!  was  ref  ractionated  by  means  of  a  tube  of  smaller 
diameter.  The  nine  fractions  that  were  obtained  were  anal- 
yzed for  their  olefin  content.  The  results  were  as  follows: 

Table  XXV 1 11 — Second  Fractionation  of  California  Oil  HI 
(Refractionation  of  3-!) 

Fraction  Sp.  gr.  Per  cent,  olefins 

3-1  i  0.8661  8.55 

3-1  2  0.8685  8.93 

3-!  3  0.8740  10. 06 

3-14  0.8751  10.82 

3-15  0.8759  io-77 

3-16  0.8773  11.40 

3-!  7  0.8782  11.67 

3-18  0.8801  11,79 

3-19  0.8807  11-89 

3-!  10  0.884  12.06 

These  results  demonstrate  that  a  further  removal  of  bitu- 
minous material  is  possible  by  ref rac donating  a  heavy  frac- 
tion, for  there  was  a  slight  loss  of  color  occasioned  by  the 
diffusion  through  the  earth.  Only  a  part  of  the  olefins  was 
removed,  however,  by  this  second  fractionation,  and  the  re- 
duction in  viscosity  was  also  very  slight. 

Efforts  were  made  to  determine  the  effect  of  shaking  frac- 
tions of  oil  with  large  amounts  of  fuller's  earth.  Accordingly 
several  portions  of  Fraction  3~E  were  shaken  with  varied  quan- 


44 

titles  of  fuller's  earth  for  different  periods  of  time.  First,  a 
quantity  was  shaken  with  three  times  its  weight  of  earth  for 
30  hours  and  separated  from  the  earth  by  suction.  It  was 
analyzed,  with  the  following  results: 

Table   XXIX — Fraction   3~E    Shaken   with   Three   Times   Its 
Weight  of  Earth 

Time  in  hours  Sp.  gr.  Per  cent,  olefins  Color 

20  0.8305  4.01  Yellow 

o  0.8524  5.05  Pale  orange 

When  shaken  with  one-half  its  weight  of  earth  for  periods 
ranging  from  10  to  50  hours,  the  following  results  were  ob- 
tained : 

Table  XXX — Fraction    3~E  Shaken  with  One-half  Its  Weight 

of  Earth 

Time  in  hours  Sp.  gr.  Per  cent,  olefins  Color 

o  0.8524  5.05  Pale  orange 

10  0.8524  5.08  Pale  orange 

20  o .  852 1  5 .  oo  Pale  orange 

30  o .  852  5 .  oo  Pale  orange 

50  0.8513  4-90  Same  color,  but 

slightly  less  fluor- 
escence 

These  results  show  that  the  time  that  an  oil  is  in  contact 
with  fuller's  earth  is  of  little  or  no  importance  as  a  factor 
in  determining  to  what  extent  the  earth  absorbs  certain  in- 
gredients from  it.  The  important  factor  is  the  amount  of 
earth  with  which  it  comes  in  contact.  These  experiments 
substantiate,  then,  the  deductions  that  are  given  on  page  88 
et  seq.j  i.  e.,  that  it  is  the  amount  of  surface  of  the  earth  to 
which  the  oil  is  exposed  that  determines  the  extent  of  its  ab- 
sorptive action. 

This  is  in  line  with  the  action  of  those  substances  whose 
surface  energy  is  capable  of  affecting  a  colloid.  That  the 
bitumen  in  the  petroleum  investigated  exists  in  this  form 
was  proved  by  the  following: 

i.  There  was  effected  an  actual  separation  of  the  petroleum 
into  two  distinct  layers  when  an  electromotive  force  of  no 


45 

volts  was  impressed  upon  parts  of  the  oil  separated  by  an  un- 
glazed  porcelain  septum.  In  order  to  make  the  oil  conduct 
the  current,  one  portion  was  shaken  for  several  hours  with 
one-fourth  its  volume  of  a  20  per  cent,  solution  of  hydro- 
chloric acid,  and  another  with  an  equal  amount  of  a  20  per 
cent,  solution  of  potassium  hydroxide.  The  emulsions  formed 
in  this  way  proved  poor  conductors,  but  were  sufficiently 
good  to  enable  the  bitumen  partially  to  precipitate  out  as  a 
brown  layer  of  a  very  viscous  liquid,  containing  no  mineral 
residue.  Its  form  indicated  that  the  bitumen  was  held  in  the 
original  petroleum  as  a  colloid — that  type  that  has  been  named 
by  Oswald  an  emulsoid. 

2.  The  high   temperature  coefficient  of   viscosity  of  Cali- 
fornia petroleum,   as    shown    by  earlier  experiments    (p.   9, 
Table  I),  is  one  of  the  most  marked  characteristics  of  emulsoids, 
i.  e.,  that  type  of  colloid  solution  in  which  the  colloid  is  a 
liquid  in  a  state  of  minute  subdivision  in  a  liquid  medium. 

3.  The  oil  and   bituminous  material   that  were  held  back 
by  the  fuller's  earth  could  not  be  removed  by  mechanical 
means.     For,  after  the  earth  had  been  extracted  with  ether  and 
carbon  tetrachloride  until  no  more  could  be  extracted,  it  yielded 
a  small  quantity  of  oil  upon  distillation.     This  showed  that 
the  bituminous  material  that  was  in  the  oil  had  undergone 
a  change  of  condition  when  it  was  adsorbed  by  the  earth. 

SUMMARY 

1.  The  diffusion  of  petroleum  through  fine-grained  fuller's 
earth  failed  to  effect  the  fractionation  of  the  petroleum  when 
the  latter  was  of  specific  gravity  as  high  as  0.912  at  20°. 
Raising  the  temperature  of  such  an  oil  to  75°  made  fractiona- 
tion possible. 

2.  The  effect  of  such  a  diffusion  of  a  petroleum  containing 
compounds  of  sulphur  is  to  separate  out  the  light  fractions  of 
the   oil   containing   smaller   proportions   of  sulphur  than   are 
found  in  the  original  petroleum. 

3.  The  effect  of  fractionating  by  means  of  diffusion  through 
fuller's  earth  of  a  petroleum  containing  nitrogen  compounds 
is  to  remove  the  nitrogen  compounds  from  the  oil  that  diffuses 


46 

upward  through  the  earth,  and  to  cause  them  to  concentrate 
in  the  earth  through  which  the  oil  has  passed. 

4.  Mixtures  of  benzene  and  paraffin  oil,  when  fractionated 
by  capillary  diffusion   through  fuller's  earth,   give  fractions 
that  have  marked  general  characteristics,  both  chemical  and 
physical,  based  on  the  proportions  of  benzene  and  paraffin 
oil  in  each. 

5.  The  f  ractionation  of  a  petroleum  rich  in  benzene  and  olefin 
hydrocarbons  by   the  diffusion   through  fuller's  earth  gives 
fractions  in  which  the  proportions  of  benzene  and  olefin  hydro- 
carbons increase  regularly  with  the  increase  in  specific  gravity 
of  the  successive  fractions. 

6.  An  explanation  of  the  above  phenomena  was  found  in 
the  conception  of  the  petroleum  as  an  emulsoid,  and  in  the 
action  of  the  fuller's  earth  as  a  dialyzing  septum,  permitting 
the  free  passage  of  the  paraffin  oils,  and  causing  by  its  ex- 
tensive surface  the  adsorption  and  coagulation  of  the  bituminous 
material,   carrying   with  it   the   sulphur   and   nitrogen   com- 
pounds and  the  benzene  and  olefin  hydrocarbons. 


BIOGRAPHY 

Philip  Schneeberger  was  born  in  Baltimore,  Maryland,  on 
November  22,  1887.  His  primary  education  was  obtained  in 
the  public  schools  of  that  city  and  at  the  Baltimore  City  Col- 
lege, from  which  he  graduated  in  1906.  His  Collegiate  educa- 
tion was  obtained  at  the  Johns  Hopkins  University,  which  he 
entered  in  1906,  and  from  which  he  received  his  A.B.  in  1909. 
Thereafter  he  pursued  graduate  courses  in  chemistry  at  the 
Johns  Hopkins  University,  and  was  laboratory  assistant  there 
in  general  inorganic  and  organic  chemistry  for  the  years 
1910-1 1  and  1912-13.  During  his  graduate  work  in  chemistry, 
since  October,  1909,  his  subordinate  subjects  have  been  physical 
chemistry  and  geology. 


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